Dunno what happened at my machine I got following
Processing files: system-config-samba-1.2.55-1.fc8
error: File not found:
/var/tmp/system-config-samba-1.2.55-1.fc8-root-mockbuild/usr/bin/system-config-samba
Executing(%doc): /bin/sh -e /var/tmp/rpm-tmp.87231
Will check again CVS and try to build it again.